[Asterisk-Dev] Channel bank w/ bri card and Zaptel

[Steven Critchfield]

Just so you know some terms listed in the Adit ISDN BRI card
documentation;

4:1 TDM is where 4 BRI lines share a DS0 for the D channel

3DS0 BRITE is where the ISDN BRI uses 3 DS0 channels and the D is on a
DS0 of it's own.

Don't know more, but this hopefully will help if you want to shake down
some documentation more than what this says. It would be nice if both
kinds of muxing are available.

Out of curiousity, wouldn't this be the same type of information as is
in the D channel of a PRI, and therefore maybe mostly implemented
already in libpri?  

On Thu, 2003-04-03 at 12:03, Steve Brown wrote:
> I have a t100p and Premisys bank w/ bri card. The bri card has 8 u ports 
> that can be configured for either terminal or network. Each port uses 3 
> ds0 channels, one for b1, b2 and d. The d channels of four ports can be 
> multiplexed on the same ds0. Each of the 4 ports is assigned 2 bits in 
> each ds0 byte. This seems pretty standard for other banks too.
> 
> Given zaptel support for the multiplexed d channel, it might not be too 
> difficult to build a low-level hisax driver for zaptel and let 
> isdn4linux do the L2/L3 stuff. I realize that i4l only does terminal 
> (not network) protocol, but it's a start.
> 
> I've experimented with an isdn phone and nt-1. L1 syncs up and a dump of 
> the d channel (configured as clear) shows the phone trying to establish 
> L2 w/ switch. All the bits seem to be where they belong.
> 
> If you already have a channel bank, this seems like a tidy way to add isdn.
> 
> Has anybody familiar with zaptel and/or hisax looked into this?
> 
> Steve
> 
> 
> 
> 
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-- 
Steven Critchfield  <critch at basesys.com>